BAGHDAD, Iraq — Two suicide vehicle bombs, including one targeting a U.S.-Iraqi army patrol, killed at least 21 people and wounded 63 in the northern city of Kirkuk Sunday, police said.

Two civilians were killed and seven were wounded in separate attacks in the city.

The first suicide bomb, in a truck, exploded in the morning in the center of the city, killing 18 and wounding 55, said police Brig. Sarhat Qadir.

A few hours later, a suicide car bomb rammed into the joint patrol in the south of the city, killing at least three bystanders and wounding eight others, Qadir said.

He said there were also casualties among the soldiers, but would not provide further details.

A gunman sitting beside the truck bomber opened fire on civilians before the vehicle exploded near the city’s criminal court and the headquarters of the two main Kurdish political parties, the Kurdistan Democratic Party and the Patriotic Union of Kurdistan, Qadir said.

The Patriotic Union of Kurdistan is run by Iraq’s President Jalal Talabani, while the president of Kurdistan, Massoud Barzani, runs the Kurdistan Democratic Party.

Barzani recently angered many in Baghdad when he ordered the Iraqi national flag to be replaced with the Kurdish banner on all government buildings in the autonomous Kurdish region in the north. Kirkuk is located just outside the autonomous region. Barzani’s Sept. 1 decision led to a particularly strong outcry among Sunni Arab lawmakers who fear that Kurds are pushing for secession under the nation’s new federal system.

In separate attacks in Kirkuk, a roadside bomb exploded near a police patrol in the south of the city, killing two civilians and wounding four, while another roadside bomb, also targeting a police patrol, wounded three civilians in another part of the city, Qadir said.